Even on days when he can play outside, 4-year-old Reco Lovett is never far from his inhaler. At age 2, he was diagnosed with asthma so severe it sent him to the hospital nine times.

"He'll say, 'I want to go outside,' and I'm like, 'No, you have to stay in you know, because it's hot,' and I'll say, 'You'll start coughing,' and he knows what that means," Lovett's mother, Marie, said.

That's because in cities like Atlanta, air quality puts him at risk, according to a new Harvard study.

Researchers studied 60 million senior citizens and found that their long-term exposure to certain air pollutants increased the risk of premature death. Those especially at risk are African Americans and low-income communities.

Atlanta has one of the highest levels of air pollutants because of congestion, its landlocked geography and heat. Los Angeles and parts of the nation's coal country are also particularly bad.

A nationwide study shows levels of air pollution that are considered to be safe increase the risk of premature deaths.

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Lovett worries about the potential long-term impacts on Reco's health.

"The most important thing is keeping him medicated, make sure he gets his medicine every day and just try to keep the triggers down," she said.

The Environmental Protection Agency says Atlanta does meet smog standards. But the study argues those standards should be revised.

Cutting air pollution nationwide by just a fraction could save 12,000 lives a year.

Downtown Atlanta, with suffers some of the highest pollution rates in the U.S.